Effect of co-modification by Ba and Sb on the microstructure of Mg2Si/Mg–Zn–Si composite and mechanism
Effect of co-modification by Ba and Sb on the microstructure of Mg2Si/Mg–Zn–Si composite and mechanism
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DOI：
10.1016/j.jallcom.2013.12.041
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发表时间：
2014-04
影响因子：
6.2
通讯作者：
Ke Chen;Zi-quan Li
中科院分区：
文献类型：
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作者：
Ke Chen;Zi-quan Li
采用原位合成的方法制备了Mg_2Si/Mg-Zn-Si复合材料，并用Ba和Sb对其进行了改性，研究了复合材料的显微组织和拉伸性能。结果表明，BaSb的共同变质有效地细化了镁硅合金的形貌：初生镁硅颗粒被变质为细小的多边形颗粒，当Ba量为1.0wt.%时，初生镁硅颗粒的平均尺寸随Sb质量分数的增加而减小；当Ba含量为1.0wt.%时，初生镁硅颗粒的平均尺寸随Sb质量分数的增加而减小；当Ba含量为1.0wt.%时，初生μ颗粒的平均尺寸随Sb质量分数的增加而减小。复合材料的极限拉伸强度和延伸率随Sb含量的增加而增加。这归因于细小的Ba2Sb颗粒的形成，而Ba2Sb颗粒是初生的Mg2Si颗粒的异质形核中心，导致了这些析出物的细小分布。细化后的镁硅颗粒的弥散分布增强了复合材料的强度，改善了塑性。
Mg2Si/Mg–Zn–Si composite wasin situsynthesized and modified by the addition of Ba and Sb; the microstructure and tensile properties of the resulting composites were investigated. Results show that the co-modification with Ba and Sb effectively refined the morphology of Mg2Si as follows: The primary Mg2Si particles were modified to fine polygonal particles <15 μm; when the Ba content was 1.0 wt.%, the average size of primary Mg2Si particles decreased with increasing Sb mass fraction. The ultimate tensile strength and elongation values of the composites increased with increasing Sb content. This was attributed to the formation of fine Ba2Sb particles that acted as the heterogeneous nucleation sites for the primary Mg2Si particles, resulting in a refined distribution of these precipitates. The dispersion of the refined Mg2Si particles strengthened the composite and improved the ductility.